Appreciate all you knowledgeable roller-delayed guys helping the noobies out.

I got my PTR9k out to the range for its first full range session this weekend, along with my AP5.  The PTR has the 80* locking piece in it.  I started unsuppressed with some Syntech 150gr stuff and the gun simply would not run it at all.  Put the can on and it ran like a champ.  I stuck the LP from my AP5 in the PTR and tried it unsuppressed and again it ran like a champ.

So I understand that the 80* LP is to prevent receiver bulge from the higher pressures and bolt speeds that come from running suppressed (and/or shouldered with a stock), but I'm wondering if there is a round that will allow the gun to run suppressed and unsuppressed without having to change the LP out?  

Thanks!

May not help you but I run my reloads 99% of the time and they run suppressed and unsuppressed in both an MP5K PDW clone and a full size AP5 and both in full auto.

I run 147Gr JRN with 3.7Gr Titegroup (I know max is 3.6)

Try 1000fps rated 147 grain like Lawman, Blazer Brass, or American Eagle (the Syntech is rated 900fps).

Like stated above - Give 147 fmj a try and get away from that Syntech........ I have read where pieces of that syntech coating is being left inside the suppressors

Rails with bumps show honest use.

Also you can get bumps in the rails where the bolt picks up the next round.

Never tried that syntech because I can never find it locally but 147gr stuff (speer lawman,blazer, etc) would also be my recommendation as it works well in my other PCCs.


Interesting that you run 1gr over max. Not getting over pressure signs with that? what maker of projectiles are you using for those? Berrys? Blue bullets?

This is the key!! Love the 147gn with 3.6’ish gn of titegroup. Really clean load too.  Less spitting in your face than commercially available subsonics.

I think most load data is conservative.  One of the guys at the SMG match used to load 147Gr 9mm with 4.0 Gr of Titegroup.  So I tried that and chrony'd it and they were borderline supersonic and pilot buddies of mine tell me not a good idea.  However, I didn't see any signs of overpressure.  So my thinking is if my powder drop drifts up or down some I would be fine.  
I think there are several commercial 147 hotter than my reloads.  The FNM 147 stuff was really hot.  Borderline supersonic and I could see rounds swelling.  I never see that with my reloads.  I also use these rounds in all my 9mm guns, pistols and full auto SMGs.  I don't like to load special ammo for specific guns.  I load 99% 147Gr for 9mm no matter what 9mm firearm I put it in.  Been using this load for probably close to 20yrs

Have you checked your bolt gap with the 80 LP? Mine was out of spec from the factory with the 100 LP and got worse when I tried an 80. Like you, mine ran like a champ without the can with both LPs being out of spec with all bullet weights. When the can went on I had problems. Once I started changing rollers out to pull the bolt gap back in then the gun started to behave more like it should suppressed

158 grain Fiocchi Subsonic?